I need to read the rules on the spoiler tags here. It happened like 6 episodes ago. I thought these season/episode discussion threads were a pretty safe place to discuss shit that happened so far in the show.

I have read all of the books, and Jaqen H'ghar (The character) is not dead. What Offensive_Brute is referring to is when Jaqen changed into a different man, Arya calls him Jaqen H'ghar, and Jaqen replies- Jaqen H'ghar is now dead.
Referring to him being a faceless man, and the name Jaqen H'ghar belonged to his old identity, which he had discarded, therefore, calling the name Jaqen H'ghar "Dead"

I don't believe that they are the same person, strictly because Daario claims to have deep passion for beauty and women, and Jaqen H'ghar was a dutiful swordsman who lived the shadowy, mysterious life of a Faceless Man.

Daario is also one of the leaders of the Second Sons- a position that takes much time and dedication to reach. Surely, at this point, Jaqen would still have been a newcomer.